Testing device for irons



May 19, 1953 F. M. MURPHY TESTING DEVICE FOR IRONS Filed May 9, 1950 28 JNVENTOR. Vflmmpg,

k/Qmi Patented May 19, 1953 UNITED STATES PATENT OFFICE 2,638,775 TESTING DEVICE FOR rnoNs Frank M. Murphy, Chicago, Ill. Application May 9,1950, Serial No. 160,874- (01. 73-1) 5 Claims.

My invention relates to an improved device to test an electric iron or similar device and display in an easily observed manner the operating condition thereof.

Domestic electric irons must maintain surface temperature with predetermined limits while ironing. This demands that the heating element of the iron be free from short circuits and open circuits and that the temperature selecting devices be in good operating condition. Since these facts cannot be reliably determined by observation of the iron or by simple temperature or electrical 'measurements, it is necessary to provide a device that indicates in simple manner the state of theiron in these respects, thereby indicating to repairmen therep'airs necessary and displaying to purchasers the fact that the iron is operating effectively.

In accordance with the present invention an iron testing device is provided which simulates closely the thermal conditions to which the iron is exposed and indicates on an inexpensive straight thermometer the efiective temperature of the face of the iron. Moreover, the device of the present invention is provided with a fuse mechanism that partakes of the temperature of the iron and interrupts the energizing circuit if that temperature becomes excessive, thereby avoiding further damage to the iron.

It is therefore a general object of the present invention to provide an improved testing device for an electric iron.

Another object of the present invention is to provide an improved electric iron testing device which protects the iron against overheating.

Further it is an object of the present invention to provide an improved electriciron testing device-wherein a simple, inexpensive, easily replaced straight thermometer indicates the operating temperature of the iron. 7

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together withfurther objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying dra-W- Figure 2 is a cross-section view through axis 2-2, Figure 1; and, I 1

Figure 3 is a pictorial circuit diagram of the tester and showing the construction of the fuse.

Referring now to Figure 1, there is shown at I! a horizontal platform upon which the iron I is placed for testing. This platform is a relatively thin sheet of asbestos hardboard or similar material capable of withstanding high temperature without damage and having relatively low thermal conductivity.- Asbestos hardboard material for this purpose may consist of highly compressed asbestos fibers bonded together by a suitable binder capable ofstanding high temperature.

A sheet metal member I2 is bent in an L- shaped configuration to define a supporting frame for the platform ll. The back end of this frame, [2a, is bentover at l2c to receive the anchoring screws and nuts l4 and [4a, respectively, which hold the platform [0. The bottom |2b of the sheet l2 has a bent up marginal portion l2d which receives the front end of the sloping panel [6. This panel is of sheet metal and at. its rear portion forms the horizontal surface lid/and the vertical wall [61). The wall lBb terminates in the backwardly extending foot I which underlies a plurality of cut-outs l2e in the base portion [2b of the frame.

It will be observed that the panel [6 is in sloping relation relative to the platform [0 and at its upper edge ltd, is below platform I0. The platform I 0 is supported from the horizontal portion lGa of the panel 16 by the sleeves I8 which are secured in position by the lengthy screws 20 which; threadedly receive the nut 20a.

The surface temperature of the iron under test is indicated by the thermometer 22. This thermometer is held in position by the scale plate 24 which is marked with temperature gradations 24a and has complementary end portions 24b which define, in conjunction with the central. portion of the plate, a passage capable of snugly receiving the thermometer 22. The plate 24 is aflixed to the panel I6 by screws or similar anchoring devices.

The temperature sensitive bulb 22a of the thermometer 22 is received in the button indicated generally at 26. This button includes a relatively large cylindrical core portion 26a-which is drilled out at 26b to receive the thermometer 22 as shown. The button "26 also has athin mar- The button 26 is of material, such as aluminum,

having good thermal conductivity so that the ginal portion 260 extending in a relatively large,-

bulb 22a partakes of the surface temperature of Since the iron rests on the top face of platthe iron even though the iron rests only on a form I0, and the member 36 terminates a presrnall part of the marginal portion 260. Since determined distance below that face, the air gap the marginal portion 260 is relatively thin and 40 is of accurately predetermined size and prothe core portion 26a is relatively small in weight 6 vides a fixed thermal resistance between the iron (taking into account the socket 262) which reand the member 36. ceives thermometer 22), the thermal capacity of The apparatus of the present invention has the button is small and it creates no significant proven highly practical and useful in testing time delay between temperature changes on the irons. The platform I!) defines a low heat casurface of the-iron and thetemperature inqie 10 pacity'surjaee'thgst simulates an qrginary ironcated by the thermometer 22. ir'igbbar'td. "i'Ihe'buttorfi'i is'ioflow heat capacity Figure 3 shows the electrical energizing cirso that the temperature indicated by thermomcuit for the iron under test. This circuit termi-r- Rater 22 represents the temperature of the iron nates in a bayonet plug 28 suitable for go 2!?9- iyi1tl19ut ime ,delay. The fuse 34 effectively intion to the usual female socket. Startifi with 15 terru ptstiie energizing circuit to the iron in the spade 28a of this plug, the circuit maybe-trance! w eyent it is'siiort circuited or the iron heats to a through socket 30 (to which the iron T is pluggegi dangerous temperature. in as shown in Figure 1), fuse socket mandrel-rear "-Moreoverftiie apparatus of the present invenlight 42, and back to the complementary-space is cheap and easy to manufacture, since 282). A resistance 44 bypasses most of the cu r- 20 y stamped parts are required s ent flow about lamp. 1,219 pre b r t portaut howerer the th m te ,2 astra sh he us 3 so key v 511125 ent flow iw 't e' an i m e atu e v attr o e ation is palticu mime ma have int cause exce si e heati g ot i terr ptesi- As sh wnfin Figu e 3 the fuss Q5 s icks! 32 cons st of a lengthy usibe ire 44 .defin ig ustin triasr'qs 'w e socke l. This Wire carries theheating'cuirent oft e iron as shown in the name 7 wire is coile a 3%. about a ore, wh chfi tlrawn swam the w n w M0; by s rin 34cmenu" of h Sims ncho ed in th e ut i 'fib a co ucti g em nt wh h h red termined emp hic is drawnib 5.1: ng u t gp si ibn- W r a short ircui exist in e ime un er est Wire 3M melts n helb pcl por ion llae cent window 3,413! If the i' overheats the oc tfi ar she d sc ibed hereafter an of 'th prising u atur sensitive nee rclati n'with tr ruse m unt d m t said plet+ g adapted t l terrupt: an electric; 9 7 of the ruse reaches y luau! a h at transfer me ber 7 to e inseam marrow and ha s: rel ti n therewith; and mush. sate fuse for'heating p a ure oi aniron bein ransferre through nt r p g po on we the bias o sp ing A i iemble cause th Wheat? of the asc oiaarta se em eratur at the iron -f Tl-hi m mber 1 Of. -kfifan el' confi uration t nsl'is' m eddd n it 'uppera i flissipate i112 that sa when. the t m--' unseat a ereconducting and 4 dc ermined Value i per 'tu're q iifs rw i testi QYYice m 0 rising as fr th ite. comm the'member 3B.

' It "will'be observed that the ber 36 is embeddedin th; p at nates in space i'relat thereof. Thuswh e'nya ro Iii as shown in partial view M an air gap of; predetermineg p tween theta-immune of the Iron and per the platform. This airgap 'proyides a 'iireqet'er; mined temperature unrerenua bewe e '1, peratur'e' of the "iron-and he tei'n r of member 3fi=and is'chsenso thatth f e. fill, leases only when the temperature Qf'th ceedsa safievalue."

we n-tum 9f us value, a heat transfer and platform and being in heat exchange relation with said fuse and With the upper surface of said platform, and an electric circuit through said fuse for heating an iron, whereby the temperature of an iron being heated upon said platform is transferred through said heat exchange member and to said fuse and is also indicated by said thermometer, while heat transferred through said platform is dissipated through said openings with the result that said fuse interrupts said circuit only when the temperature of an iron being heated exceeds a predetermined value.

3. A testing device for electric irons or the like, comprising a frame having open ends providing outlets for the dissipation of heat, a platform mounted upon said frame and being adapted to support an iron and being formed of a material having relatively low heat conductivity properties, a mercury thermometer mounted upon said frame and having the temperature sensitive portion thereof in heat exchange relation with the upper surface of said platform, a thermal responsive fuse equipped with a shield and mounted upon said frame in spaced relation with said platform and being adapted to interrupt an electric circuit when the temperature of the fuse reaches a predetermined value, a heat transfer member of relatively high heat conductivity extending between said fuse and platform and being in heat exchange relation with said fuse and with said platform and receives the temperature sensitive portion of said thermometer.

5. The structure of claim 4 in which said platform is provided with an aperture and an end of said heat transfer member is embedded in said aperture.

FRANK M. MURPHY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,548,489 Sears Aug. 4, 1925 1,613,194 Ratterman Jan. 4, 1927 1,691,247 Matthews Nov. 13, 1928 2,447,580 Kaumans Aug. 24, 1948 2,541,121 Sparklin Feb. 13, 1951 

